US Forest Service, Sequoia National Forest
Contact: Geri Adams, (760) 417-1971
Drilling Work To Begin At Auxiliary Dam

Lake Isabella, CA., September 22, 2009...In line with the United States Army Corps of Engineers (USACE) direction to monitor the safety of the Lake Isabella Auxiliary Dam on the Kern River Ranger District of the Sequoia National Forest, the U. S. Forest Service announced today that the environmental analysis has been completed and the special use permit is being finalized that allows the USACE to start exploritory drilling and trenching operations above and below the Auxiliary Dam on National Forest System land. The purpose for drilling these holes is to determine the foundation characteristics and depth to bedrock upstream of Auxiliary Dam for the seismic evaluation.

Pending finalization of the special use permit, the USACE will begin drilling a series of 21 holes. Fifteen holes will be below the dam and six will be above the dam. The holes will be 6-8 inches in diameter and 160-250 feet deep. Later this year, the USACE will excavate a trench below the dam approximately 1,500 feet long, five feet wide, and 20 feet deep. After sampling is completed, USACE will back-fill holes with a cement-grout mix and fill the trench with the soil removed from the trench and use existing vegetation and rice straw to cover disturbed areas.

Drilling above the dam in the Auxiliary Dam Recreation Area could start as early as October 5, 2009. This drilling should take six to eight weeks to complete. The holes will be located within 600 feet of Auxiliary Dam in the area between Borel Canal and State Highway 178. Each drill site will require an area measuring approximately 100 feet by 50 feet to conduct the drilling and to stage equipment. Drilling equipment will consist of one ten-wheel truck-mounted drill rig and three support trucks.

District Ranger Rick Larson stated that overnight camping and day use activities will not be affected by the work being done by USACE. Larson also wants to remind visitors to stay safe while recreating at Auxiliary Dam by keeping clear of the work being done by USACE.